Trifluormethylpyridone based indolenine methine dyes

ABSTRACT

Indoleninemethine dyes of the formula ##STR1## where the ring A is substituted or unsubstituted, R 1  is hydrogen, substituted or unsubstituted C 1  -C 13  -alkyl, C 3  -C 4  -alkenyl, C 5  -C 7  -cycloalkyl or substituted or unsubstituted phenyl, and 
     R 2  is substituted or unsubstituted C 1  -C 13  -alkyl, C 3  -C 4  -alkenyl, substituted or unsubstituted phenyl or substituted or unsubstituted amino, 
     are useful for dyeing or printing synthetic materials and can be thermally transferred.

DESCRIPTION

The present invention relates to novel pyridone dyes of the formula I##STR2## where the ring A is substituted or unsubstituted, R¹ ishydrogen, C_(l) -C₁₃ -alkyl with or without substitution and with orwithout interruption by from 1 to 4 oxygen atoms in ether function, C₃-C₄ -alkenyl, C₅ -C₇ -cycloalkyl or substituted or unsubstituted phenyl,and

R² is C₁ -C₁₃ -alkyl with or without substitution and with or withoutinterruption by from 1 to 4 oxygen atoms in ether function, C₃ -C₄-alkenyl, substituted or unsubstituted phenyl or a radical of theformula NE¹ E², where E¹ and E² are identical or different and each isindependently of the other hydrogen, C₁ -C₁₃ -alkyl with or withoutsubstitution and with or without interruption by from 1 to 3 oxygenatoms in ether function, C₅ -C₇ -cycloalkyl, substituted orunsubstituted phenyl, substituted or unsubstituted pyridyl, substitutedor unsubstituted C₁ -C₁₃ -alkanoyl, C₁ -C₁₃ -alkoxycarbonyl, substitutedor unsubstituted C₁ -C₁₃ -alkylsulfonyl, C₅ -C₇ -cycloalkylsulfonyl,substituted or unsubstituted phenylsulfonyl, substituted orunsubstituted pyridylsulfonyl, substituted or unsubstituted benzoyl,pyridylcarbonyl or thienylcarbonyl, or E¹ and E² join with the linkingnitrogen atom to form unsubstituted or C₁ -C₄ -alkyl-substitutedsuccinimido, unsubstituted or C_(l) -C₄ -alkyl-substituted phthalimidoor a 5- or 6-membered saturated heterocyclic radical with or withoutfurther hetero atoms,

to a process for dyeing or printing synthetic materials using the noveldyes and to a process for their thermal transfer.

JP-A-339 237/1993 describes the preparation of1-alkyl-3-cyano-4-trifluoromethyl-6-hydroxypyrid-2-ones. Furthermore,WO-A-96/15 195 discloses methine and azamethine dyes based ontrifluoromethylpyridones.

It is an object of the present invention to provide novelindoleninemethine dyes having advantageous application properties fortextile application.

We have found that this object is achieved by the indoleninemethine dyesof the formula I defined at the outset.

Any alkyl or alkenyl appearing in the abovementioned formulae may bestraight-chain or branched.

Substituted alkyl appearing in the abovementioned formulae may havesubstituents for example, unless otherwise stated, cyclohexyl,substituted or unsubstituted phenyl, C₁ -C₈ -alkanoyloxy, C₁ -C₈-alkylaminocarbonyloxy, C₁ -C₈ -alkoxycarbonyl, C₁ -C₈-alkoxycarbonyloxy, the alkyl chain in the last three radicals beingoptionally interrupted by from 1 to 3 oxygen atoms in ether function andoptionally phenyl- or phenoxy-substituted, cyclohexyloxy, phenoxy,halogen, hydroxyl, cyano, pyrazoyl or C₁ -C₄ -dialkylamino. Substitutedalkyl generally has 1 or 2 substituents.

Alkyl in the abovementioned formulae which is interrupted by oxygenatoms in ether function is preferably alkyl interrupted by 1 or 2 oxygenatoms in ether function.

Substituted phenyl or pyridyl in the abovementioned formulae may havesubstituents for example, as in ring A, C₁ -C₈ -alkyl, C₁ -C₈ -alkoxy,halogen, especially chlorine or bromine, nitro, cyano or C₁ -C₄-alkoxycarbonyl. Substituted phenyl or pyridyl generally has from 1 to 3substituents.

Suitable R¹, R², E¹ and E² are each for example methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl,neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl,2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl,dodecyl, tridecyl, isotridecyl [The designations isooctyl, isononyl,isodecyl and isotridecyl are trivial names derived from the alcoholsobtained by the oxo process (cf. Ullmann's Encyclopedia of IndustrialChemistry, 5th Edition, Vol. A1, pages 290 to 293, and also Vol. A 10,pages 284 and 285).], 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl,2-butoxyethyl, 2- or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2- or3-propoxypropyl, 2- or 3-butoxypropyl, 2- or 4-methoxybutyl, 2- or4-ethoxybutyl, 2- or 4-butoxybutyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl,4,8-dioxanonyl, 3,7-dioxaoctyl, 3,7-dioxanonyl, 4,7-dioxaoctyl,4,7-dioxanonyl, 4,8-dioxadecyl, 3,6,9-trioxadecyl, 3,6,9-trioxaundecyl,3,6,9,12-tetraoxatridecyl, 3,6,9,12-tetraoxatetradecyl, phenyl, 2-, 3-or 4-methylphenyl, 2-, 3- or 4-ethylphenyl, 2-, 3- or 4-propylphenyl,2-, 3- or 4-isopropylphenyl, 2-, 3- or 4-butylphenyl,2,4-dimethylphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-ethoxyphenyl,2-, 3- or 4-isobutoxyphenyl, 2,4-dimethoxyphenyl, 2-, 3- or4-chlorophenyl, 2,6-dichlorophenyl, 2-, 3- or 4-nitrophenyl 2-, 3- or4-carboxyphenyl, 2-, 3- or 4-cyanophenyl, 2-, 3- or 4-methoxy- orethoxycarbonylphenyl, benzyl, 2-methylbenzyl, 1- or 2-phenylethyl,2-hydroxyethyl, 2- or 3-hydroxypropyl, 2-cyanoethyl, 2- or3-cyanopropyl, 2-acetyloxyethyl, 2- or 3-acetyloxypropyl,2-isobutyryloxyethyl, 2- or 3-isobutyryloxypropyl,2-methoxycarbonylethyl, 2- or 3-methoxycarbonylpropyl,2-ethoxycarbonylethyl, 2- or 3-ethoxycarbonylpropyl,2-methoxycarbonyloxyethyl, 2- or 3-methoxycarbonyloxypropyl,2-ethoxycarbonyloxyethyl, 2- or 3-ethoxycarbonyloxypropyl,2-butoxycarbonyloxyethyl, 2- or 3-butoxycarbonyloxypropyl,2-(2-phenylethoxycarbonyloxy)ethyl, 2 or 3-(2-phenylethoxycarbonyloxy)propyl, 2-(2-ethoxyethoxycarbonyloxy)ethyl or 2-or 3-(2-ethoxyethoxycarbonyloxy)propyl.

R¹, E¹ and E² may each also be for example cyclopentyl, cyclohexyl orcycloheptyl.

E¹ and E² may each also be for example pyridyl, 2-, 3- or4-methylpyridyl, 2-, 3- or 4-methoxypyridyl, formyl, acetyl, propionyl,butyryl, isobutyryl, pentanoyl, hexanoyl, heptanoyl, octanoyl,2-ethylhexanoyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl,isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl,sec-butoxycarbonyl, methylsulfonyl, ethylsulfonyl, propylsulfonyl,isopropylsulfonyl, butylsulfonyl, cyclopentylsulfonyl,cyclohexylsulfonyl, cycloheptylsulfonyl, phenylsulfonyl, tolylsulfonyl,pyridylsulfonyl, benzoyl, 2-, 3- or 4-methylbenzoyl, 2-, 3- or4-methoxybenzoyl, thien-2-ylcarbonyl or thien-3-ylcarbonyl.

R¹ and R² may each also be for example allyl or methallyl.

E¹ and E² joined together with the linking nitrogen atom to form a 5- or6-membered saturated heterocyclic radical with or without further heteroatoms may be for example pyrrolidinyl, piperidinyl, morpholinyl,piperazinyl or N- (C₁ -C₄ -alkyl) piperazinyl.

Preference is given to indoleninemethine dyes of the formula I where thering A is unsubstituted.

Preference is further given to indoleninemethine dyes of the formula Iwhere R¹ is C₁ -C₄ -alkyl with or without phenyl substitution.

Preference is further given to indoleninemethine dyes of the formula Iwhere R² is C₁ -C₉ -alkyl with or without interruption by from 1 to 3oxygen atoms in ether function and with or without hydroxyl or phenylsubstitution or phenyl.

Particular preference is given to indoleninemethine dyes of the formulaI where R² is C₁ -C₆ -alkyl with or without interruption by 1 or 2oxygen atoms in ether function.

Preference is further given to indoleninemethine dyes of the formula Iwhere R¹ is methyl or benzyl.

The novel indoleninemethine dyes of the formula I can be prepared bymethods known per se.

For example, they can be obtained by condensation of aldehydes of theformula II ##STR3## where the ring A and R¹ are each as defined above,with trifluoromethylpyridones of the formula III ##STR4## where R² is asdefined above.

The intermediates for preparing the novel indoleninemethine dyes aregenerally compounds known per se.

It has also been found that synthetic materials can be advantageouslydyed or printed by treating them with one or more of the dyes of theinvention. Examples of synthetic materials are polyesters, polyamides orpolycarbonates. Particularly suitable synthetic materials are materialsin textile form, such as fibers, yarns, threads, knits, wovens ornonwovens composed of polyester, modified polyester, for exampleanionically modified polyester, blends of polyester with cellulose,cotton, viscose or wool, or polyamide. The dyeing and printingconditions are known per se and also include dyeing in supercriticalcarbon dioxide. The dyeings or prints obtained have high lightfastness,high brilliance and very good wetfastnesses, for example very good washor perspiration fastness.

The present invention further provides a process for transferring dyesfrom a transfer to polymer-coated paper by diffusion or sublimation withthe aid of an energy source, which comprises using a transfer comprisingone or more indoleninemethine dyes of the formula I.

To make the transfers required for the process of the present invention,the dyes of the formula I are incorporated in a suitable organic solventor a mixture of solvents with one or more binders with or withoutauxiliaries to form a printing ink. This printing ink preferablycontains the dyes of the formula I in a molecularly disperse, ie.dissolved, form. The printing ink can be applied to the inert support bymeans of a doctor blade and air dried. Suitable organic solvents for thedyes of the formula I include for example those in which the. solubilityof the dyes of the formula I at a temperature of 20° C. is greater than1% by weight, preferably greater than 5% by weight.

Examples are ethanol, propanol, isobutanol, tetrahydrofuran, methylenechloride, methyl ethyl ketone, cyclopentanone, cyclohexanone, toluene,chlorobenzene or mixtures thereof.

Suitable binders include all resins or polymer materials which aresoluble in organic solvents and which are capable of binding the dye tothe inert support sufficiently firmly as to prevent rubbing off.Preference is given to those binders which, after the air drying of theprinting ink, include the dye in the form of a clear, transparent filmwithout any visible crystallization of the dye.

Such binders are mentioned for example in U.S. Pat. No. 5,132,438 or inthe pertinent patent applications cited therein. Also suitable aresaturated linear polyesters.

Preferred binders include ethylcellulose, ethylhydroxyethyl-cellulose,polyvinyl butyral, polyvinyl acetate, cellulose propionate or saturatedlinear polyesters.

The weight ratio of binder: dye generally ranges from 1:1 to 10:1.

Suitable auxiliaries include for example release agents as mentioned inU.S. Pat. No. 5,132,438 or the pertinent patent applications citedtherein. Also suitable are especially organic additives which preventthe crystallizing out of the transfer dyes in the course of storage oron heating of the color ribbon, for example cholesterol or vanillin.

Suitable inert supports are described for example in U.S. Pat. No.5,132,438 or in the pertinent patent applications cited therein. Thethickness of the support generally ranges from 3 to 30 μm.

Suitable dye receiver layers include in principle all thermally stableplastics layers with affinity for the dyes to be transferred, forexample modified polycarbonates or polyesters. Further details can befound for example in U.S. Pat. No. 5 132 438 or the pertinent patentapplications cited therein.

The process of transfer is effected by means of an energy source, forexample by means of a laser or a thermal head, for which the latter hasto be heatable to a temperature of ≧300° C. so that the transfer of thedye can take place within the time range t: 0<t<15 msec. The dyemigrates out of the transfer sheet and diffuses into the surface coatingof the receiving medium.

The dyes of the formula I of the present invention are notable foradvantageous dye transfer application properties. They exhibit highsolubility in the color ribbon (good compatibility with the binder), ahigh stability in the printing ink, good transferability, high imagestability (ie. good lightfastness and also good stability toenvironmental effects, for example moisture, temperature or chemicals),and permit flexible coloristic adaptation to given subtractive primarycolors as part of an optimal trichromat (highest possible brilliance ofprimary or secondary colors and deep neutral black).

The novel indoleninemethine dyes are also useful for printing materialsby means of the inkjet process. Suitable substrates are for examplepaper, glass, ceramics, plastics and metals as well as those mentionedabove.

The dyes of the invention can also be used for dyeing keratinous fibers,for example in hair dyeing or the dyeing of furs.

The novel dyes of the formula I are also advantageously useful for themanufacture of color filters as described for example in EP-A-399 473.

Finally, they can also be used with advantage as colorants for themanufacture of toners for electrophotography.

The Examples which follow illustrate the invention.

EXAMPLE 1

a) 100 ml of methanol and 29 g of n-hexylamine (0.287 mol) were chargedinitially and admixed at 30-35° C. with 32.8 g (0.287 mol) of ethylcyanoacetate over 2 h. The mixture was subsequently stirred at 30° C.for 2 h. 25 g of piperidine were added, followed by 52.8 g (0.287 mol)of ethyl 4,4,4-trifluoroacetoacetate. The reaction mixture was thenrefluxed for 14 h and the solvent was removed at a temperature rising to100° C. The rest was added while still hot to 450 g of ice and 75 ml ofconcentrated hydrochloric acid. The product was filtered off withsuction, washed neutral with cold water and dried at 50° C. underreduced pressure, leaving 79.3 g of pyridone of formula ##STR5## yield:95.9% b) 4.0 g (0.02 mol) of aldehyde of the formula ##STR6## and 5.8 g(0.02 mol) of the compound described in Example 1a) were heated to 130°C. in 20 ml of acetic anhydride for 30 min. Cooling brought down aprecipitate of a brilliant red dye of the formula ##STR7## which wasfiltered off with suction, washed with a little methanol and dried at50° C. under reduced pressure.

Yield: 6.6 g (70%)

λ_(max) : 538 nm (CH₂ Cl₂)

EXAMPLE 2

a) To 210 ml of methanol and 118.3 g of 3-(2-phenoxyethoxy)propylamine(0.6 mol) were added, over 2 h, 67.9 g (0.6 mol) of ethyl cyanoacetateat from 30 to 35° C. The mixture was subsequently stirred at 30° C. for2 h. 52.3 g of piperidine were added, followed by 110.4 g (0.6 mol) ofethyl 4,4,4-trifluoroacetoacetate. The reaction mixture was thenrefluxed for 14 h and the solvent was removed at a temperature rising to100° C. The remainder was added while still hot to 1 l of ice and 157 mlof concentrated hydrochloric acid. The aqueous mixture was extractedwith 500 ml of ethyl acetate, dried over sodium sulfate and subjected toreduced pressure to remove the solvent, leaving 201 g (87.5% yield) ofthe pyridone of the formula ##STR8## b) 4.0 g (0.02 mol) of aldehyde ofthe formula ##STR9## and 7.6 g (0.02 mol) of the compound described inExample 2a) were heated to 130° C. in 20 ml of acetic anhydride for 30min. After cooling, the precipitated dye of the formula ##STR10## wasfiltered off with suction, washed a little methanol and dried at 50° C.under reduced pressure.

Yield: 6.25 g (57.8 %)

λ_(max) : 536 nm (CH₂ Cl₂)

EXAMPLE 3

a) To 35.4 g (0.6 mol) of propylamine were added dropwise, at 30-35° C.,67.9 g of ethyl cyanoacetate (0.6 mol). The mixture was subsequentlystirred at 30° C. for 2 h. Then 52.5 g of piperidine (0.61 mol) and111.6 g (0.6 mol) of ethyl 4,4,4-trifluoroacetoacetate were addeddropwise. The temperature rose to 53° C. The mixture was then refluxedfor 10 h. The solvent was distilled off after the reaction had ended,and the remaining residue was poured hot into a mixture of 1 l ofice-water and 160 ml of concentrated hydrochloric acid. The productcrystallized out at 5° C. in the course of 1 h, was filtered off withsuction and washed neutral with a little water and dried at 50° C. underreduced pressure, leaving 205 g of the pyridone of the formula ##STR11##b) 4.0 g of aldehyde (0.02 mol) ##STR12## and 4.92 g (0.02 mol) of thepyridone described in Example 3a were heated to 130° C. in 20 ml ofacetic anhydride for 30 min. Cooling brought down a precipitate of a reddye of the formula ##STR13## which was filtered off with suction, washedwith methanol and dried at 50° C. under reduced pressure.

Yield: 6.5 g (76%)

λ_(max) : 536 nm (CH₂ Cl₂)

The same method is used to obtain the dyes of the formula ##STR14##recited in Table 1 below:

                  TABLE 1                                                         ______________________________________                                                                         .sub.max                                       Ex. No. R.sup.1 R.sup.2 [nm] (in CH.sub.2 Cl.sub.2)                         ______________________________________                                         4    CH.sub.3  C.sub.2 H.sub.4 C.sub.6 H.sub.5                                                                536                                             5 CH.sub.3 CH.sub.2 C.sub.6 H.sub.5 536                                       6 CH.sub.3 CH.sub.3 536                                                       7 CH.sub.3 C.sub.4 H.sub.9 536                                                8 CH.sub.3 C.sub.2 H.sub.5 536                                                9 CH.sub.3 (CH.sub.2).sub.3 OCH.sub.3 536                                    10 CH.sub.3 (CH.sub.2).sub.2 OC.sub.2 H.sub.5 536                             11 CH.sub.3 (CH.sub.2).sub.3 O(CH.sub.2).sub.2 OCH.sub.3 536                   - 12 CH.sub.3                                                                                                 536 15##                                      - 13 CH.sub.3 (CH.sub.2).sub.3 --N(CH.sub.3).sub.2 536                       14 CH.sub.3 C.sub.5 H.sub.11 537                                              15 CH.sub.3 CH.sub.2 CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9 536                   16 CH.sub.3 C.sub.6 H.sub.5 538                                               17 CH.sub.3 (CH.sub.2).sub.2 OH 536                                           18 CH.sub.3 (CH.sub.2).sub.2 OCOCH.sub.3 536                                  19 C.sub.6 H.sub.5 C.sub.6 H.sub.13 537                                       20 CH.sub.2 C.sub.6 H.sub.5 C.sub.6 H.sub.13 536                              21 CH.sub.2 C.sub.6 H.sub.5 C.sub.4 H.sub.9 536                               22 (CH.sub.2).sub.2 C.sub.6 H.sub.5 C.sub.6 H.sub.13 542                      23 (CH.sub.2).sub.2 C.sub.6 H.sub.5 C.sub.3 H.sub.6 OC.sub.2 H.sub.4                                         OC.sub.6 H.sub.5 542                           24 (CH.sub.2).sub.2 C.sub.6 H.sub.5 C.sub.3 H.sub.7 542                       25 (CH.sub.2).sub.2 C.sub.6 H.sub.5 C.sub.3 H.sub.6 OCH.sub.2 CH(C.sub.2                                      H.sub.5)C.sub.4 H.sub.9 542                   26 (CH.sub.2).sub.2 C.sub.6 H.sub.5 C.sub.2 H.sub.4 OC.sub.2 H.sub.5                                         542                                            27 CH.sub.3 C.sub.3 H.sub.6 OC.sub.2 H.sub.4 OC.sub.2 H.sub.5 540                                             28 CH.sub.3 C.sub.3 H.sub.6 OCH.sub.2                                        CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9 540                                         29 C.sub.4 H.sub.9 C.sub.4 H.sub.9 538                                        30 C.sub.4 H.sub.9 C.sub.3 H.sub.6                                           OCH.sub.2 CH(C.sub.2 H.sub.5)C.sub.4                                          H.sub.9 540                                    31 C.sub.6 H.sub.13 (CH.sub.2).sub.2 C.sub.6 H.sub.5 540                      32 CH.sub.3 C.sub.3 H.sub.6 OCH.sub.2 C.sub.6 H.sub.5 538                     33 CH.sub.3 C.sub.2 H.sub.4 OC.sub.6 H.sub.4 -p-OCH.sub.3 538                 34 CH.sub.3 CH(CH.sub.3)C.sub.3 H.sub.6 CH(CH.sub.3)CH.sub.3 538                                              35 CH.sub.3 C.sub.3 H.sub.6 OC.sub.3                                         H.sub.7 538                                  ______________________________________                                    

Use in dyeing

10 g of a woven polyester fabric are introduced at 50° C. into 200 ml ofa dyeing liquor which contains X% by weight, based on the polyesterfabric, of dye and whose pH has been set at 4.5 by means of acetic acid.The fabric was treated at 50° C. for 5 min, the temperature of theliquor was then raised to 130° C. over 30 min, maintained for 60 min atthat level and then cooled back down to 60° C. over 20 min.

The dyed polyester fabric was then reduction cleared by treating it at65° C. in 200 ml of a liquor containing 5 ml/l of 32% strength by weightaqueous sodium hydroxide solution, 3 g/l of sodium dithionite and 1 g/lof an addition.product of 48 mol of ethylene oxide with 1 mol of castoroil for 15 min. The fabric was finally rinsed, neutralized with diluteacetic acid, rinsed once more and dried.

Dyes No. 1 to 35 were each employed in an amount (X) of 0.3% by weight.The dyeings obtained were a very brilliant red color and had excellentlightfastness.

Application in thermal transfer:

a) 10 g of dye are stirred, if necessary with brief heating to 80-90°C., into 100 g of a 10% strength by weight solution of a polyvinylbutyral binder in 4.5:2:2 v/v/v methyl ethylketone/toluene/cyclohexanone.

The mixture is applied with a 10 μm doctor blade to a 6 μm thickpolyester film which has a suitable slipping layer on the back and isblown dry with a hair dryer in the course of 1 minute. Before the colorribbon can be printed, it has to be air dried for at least a further 24hours, since residual solvents can impair the printing process.

b) The color ribbons are printed on an experimental computer-controlledapparatus equipped with a commercial thermal printing head ontocommercial Color Videoprint Paper (from Hitachi).

The voltage is altered to control the energy emitted by the thermalprinting head, the length of a pulse having been set to 7 ms and onlyone pulse being emitted at a time. The emitted energy level ranges from0.5 to 2.0 mJ/dot.

Since the depth of the color is directly proportional to the suppliedenergy, it is possible to produce a color wedge for spectroscopicevaluation.

The depth of the color is plotted against the supplied energy perheating element to determine the Q* value (=energy in mJ for theabsorbance value of 1) and the gradient m in 1/mJ.

The results obtained are listed in Table 2 below.

                  TABLE 2                                                         ______________________________________                                          Dye No.                                                                                               #STR16##                                                                     ##STR17##                                            ______________________________________                                        1              0.93     2.89                                                    2 0.94 2.54                                                                   4 0.98 2.65                                                                   5 1.00 2.25                                                                   7 0.93 2.85                                                                   11 0.91 2.84                                                                  15 0.98 2.67                                                                ______________________________________                                    

We claim:
 1. Indoleninemethine dyes of the formula I ##STR18## where thering A is substituted or unsubstituted,R¹ is C₁ -C₄ -alkyl with orwithout substitution by phenyl, and R² is C₁ -C₉ -alkyl with or withoutinterruption by from 1 to 3 oxygen atoms in either function and with orwithout hydroxyl or phenyl substitution or phenyl.
 2. Indoleninemethinedyes as claimed in claim 1, wherein the ring A is unsubstituted.
 3. Aprocess for transferring dyes from a transfer to polymer-coated paper bydiffusion or sublimation with the aid of an energy source, whichcomprises using a transfer comprising one or more indoleninemethine dyesof the formula I as set forth in claim
 1. 4. A process for dyeing orprinting synthetic materials, which comprises treating the syntheticmaterials with one or more indoleninemethine dyes as claimed in claim 1.